No one factor causes acne. Acne happens when sebaceous (oil) glands attached to the hair follicles are stimulated at the time of puberty by elevated levels of male hormones. Sebum (oil) is a natural substance which lubricates and protects the skin. Associated with increased oil production is a change in the manner in which the skin cells mature so that they are predisposed to clog the follicular openings or pores. The clogged hair follicle gradually enlarges, producing a bump. As the follicle enlarges, the wall may rupture, allowing irritating substances and normal skin bacteria access into the deeper layers of the skin, ultimately producing inflammation.
All acne is a disorder of the pilosebaceous unit, which is made up of a hair follicle, sebaceous gland, and a hair. These units are found everywhere on the body except on the palms, soles, top of the feet, and the lower lip. The number of pilosebaceous units is greatest on the face, upper neck, and chest. Sebaceous glands produce a substance called sebum, which is responsible for keeping the skin and hair moisturized. During adolescence sebaceous glands enlarge and produce more sebum under the influence of hormones, also called androgens. After about age 20, sebum production begins to decrease.The cause of pimples is unknown. The process by which a pimple develops is highly intricate. While we do know that a pore collapses on itself and blocks sebum (oil) from escaping, we do not fully understand why this process takes place in one sebaceous gland versus another.
